Gaseous electric discharge lamp device



P 1940- 4 ZECHER El Al. 2,213,796

GASEOUS ELECTRIC DISCHARGE LAMP DEVICE Original Filed March 10, 19;?

INVENTORS Gustav Zec her Willem Ua'terhoeve BY 6 AT ORNEY Patented Sept.3, 1940.

UNITED sTArss G ASEOUS ELECTRIC DISCHARGE LAIVIP DEVICE Gustav Zecherand Willem Uyterhoeven, Eindhoven, Netherlands, assignors to GeneralElectric Company, a corporation of New York ApplicationgMarch 10, 1937,Serial No. 130,154.

Renewed April 5, 1939.

or boric acid. When desired, a fluorescent ma- 6 Claims.

The present invention relates to gaseous electric discharge lamp devicesgenerally and more particularly the invention relates to such deviceshaving a container consistirfg in whole or in part of a fluorescent]glass which transforms certain rays emitted by the gaseous electricdischarge into rays of longer wave length to complement and supplementthe visible light emit ted by said discharge and to increase the outputof visible light from the gaseous electric discharge lamp device. Thefluorescent container glass transforms certain invisible rays intovisible rays and transforms certain visible rays into other visible raysto which the eye is more sensitive.

We have observed that fluorescent container glasses depreciate rapidlyduring-the operation of the gaseous electric discharge lamp device andthat the depreciation thereof is so great as to terminate the usefullife of a lamp device comprising such a container glass after arelatively short period of operation.

The object of the present invention is to provide a long lived gaseouselectric discharge lamp device comprising a fluorescent glass container.Another object of the invention is to provide means for minimizing thedepreciation of fluorescent glass containers for gaseous electricdischarge lamp devices. A further object of the invention is to increasethe output of visible light and to improve the color of the light from agaseous electric discharge lamp. device having a container consisting inwhole or in part of fluorescent glass. Still further objects andadvantages attaching to the device and to its use and operation will beapparent to those skilled in the art from the following particulardescription.

We have discovered that the fluorescent container glasses aredeleteriously affected by the gaseous electric discharge in said lampswhich causes a rapid reduction in the fluorescent light output of suchglasses and, of course, in the light output of the lamp. The inventionattains its objects by covering the inner surface of the fluorescentcontainer glass with a material which is resistant to the effects of thegaseous electric discharge and which transmits the visible light raysfrom the discharge and the rays which cause light emission by thefluorescent-container glass. The protective covering or coating isapplied to the inner surface of the-fluorescent glass container byflowing or spraying during the manufacture of the lamp device and,preferably,

consists, in whole or in part, of. phosphoric acid In Germany March 12,

terial, such as zinc silicate, is applied in or on the protectivecoating which coating serves as a binder for the fluorescent material.The use of the fluorescent material in or on the protective coating isparticularly advantageous because .greater luminous efficiencies andmany more striking color effects are attained.

In the drawing accompanying and forming part of this specification Fig.l is a side elevational, partly sectional view of a gaseous electricdischarge lamp device embodying the invention, and

Fig. 2 is a pair of curves one showing raphically the light output of agaseous electric dis.- charge lamp device embodying the invention andthe other showing the light output of a similar lamp not embodying theinvention;

Referring to Fig. 1 of the'drawing the gaseous electric dischargedevicecomprises an elongated,

' tubular container I having electrode chambers 2 and 2 at the endsthereof and electrodes 3 and 3 sealed therein and mounted in saidchambers an activating material, such as barium oxide.

Said container I has luminosity producing gaseous atmosphere therein,such as rare gas, metal vapor, or a gas and metal vapor mixture, whichemits rays under excitation by the discharge between said electrodes 3and 3 capable of causing the emission of light from fluorescent glasses.Preferably the gaseous atmosphere consists of a mixture of neon, argonand mercury vapor. The part 4 of the container I surrounding thedischarge path between said electrodes 3 and. 3 consists of aboro-silicate, ultra-violet transmitting glass having metal phosphors,such as tin or copper, incorporated therein whichemit light underradiation from the gaseous electric discharge between said electrodes 3and 3'. The inner surface of the container part4 has a. coating 5 ofmaterial, such as boric acid, which is more resistant to the eflects ofthe discharge than the fluorescent glass of container part 4 and whichtransmits the visible light and the phosphor exciting radiation emittedby the gaseous electric discharge. While the coating 5 is shown as beingof substantial thickness for clarity of illustration, it will beunderstood that said coating 5 is preferably a thin one. Preferably thecoating 5 has a fluorescent coating 6 applied thereto which coatingtransmits the radiations from the discharge and emits light whenirradiated. The coating 5 also transmits the visible light emitted bythe fluorescent coating 6. A fluorescent coating 6 of zinc silicate,which emits a whitish yellow light, is desirable.

Curve I of Fig. 2 of the drawing represents the light output of agaseous electric discharge lamp device similar to that illustrated inFig. 1 but not having the protective coating 5 nor the fluorescentcoating 6 thereon. In plotting the curve the initial light output of thelamp was taken as 100%. As is apparent fromaan inspection of the curve Ithe light output of the gaseous electric discharge lamp devicediminishes rapidly and is only one half its original value after thelamp has been operating only 250 hours. After the lamp has beenoperating 1000 hours the light output thereof is about A; of itsoriginal value. 1

Curve II of Fig. 2 represents the light output of'a gaseous electricdischarge lamp device similar to: that shown in Fig. 1 of the drawingand embodying the invention. The light output of.

the lamp was measured in the same manner and the lamp was .operatedunder the same condi' tions as the lamp from which the values for curveI were taken. From an inspection of the curve II it is apparent that thelight output of the lamp decreased at a much slower rate and that thelight output thereof was more than 50%' of its original value even afterthe lamp had been operating 1500 hours. A gaseous electric dischargelamp device embodying the present invention not only depreciates inlight output at a slower rate, as indicated by the curves I and II, butalso has a greater light output, due to the fluorescent coating 5, thanprior lamps in which the fluoresa cent glass of the container wasexposed to the discharge and the fluorescent coating 6 was missmg.

While we have shown anddescribed and have pointed out in the annexedclaims certain novel features of the invention, it will be understoodthat various omissions, substitutions and changes in the forms anddetails of the device illustrated and-in its use and operation may bemade by those skilled in the art without departing from the broad spiritand scope of the invention, for example, the container I has the shapeof a symbol, or a letter useful in advertising, when desired, thermionicelectrodes of the activated type are used in place of the coldelectrodes 3 and 3 when desired, and said thermionic electrodes areheated to an electron emitting arc discharge supporting temperature by aseparate heater current or by the discharge current flow therethroiughand the Voltage drop thereat, when de sire What we claim as new anddesire to secure by Letters Patent of the United States is:

l. A gaseous electric discharge lamp device comprising a container,electrodes sealed there'- in, a gaseous atmosphere therein rich in ultraviolet rays when excited by a discharge betweensaid electrodes and aprotective coating on the inner surface of said container, saidcontainer consisting of ultra violet transmitting glass havingincorporated therein a material capable of light emission underexcitation by radiation from the gaseous electric discharge between saidelectrodes, said container glass being deleteriously affected by saiddischarge, said coating covering the part of said containerincorporating said light emitting material and consisting of a materialpermeable to said exciting radiation and which is capable ofresistingthe effects of said discharge to reduce the depreciation ofsaid lamp.

2. A gaseous electric discharge lamp device comprising a container,electrodes sealed therein, a gaseous atmosphere therein rich in ultraviolet rays when excited by a discharge between said electrodes, aprotective coating on the inner surface of said container and a quantityof fluorescent material adherent to said coating, said containerconsisting of ultra violet transmitting glass having incorporatedtherein a material capable of light emission under excitation byradiation from the gaseous, electric discharge between said electrodes,said container glass being deleteriously affected by said discharge,said coating covering said light emitting container part and consistingof a material permeable to said exciting radiation and which is capableof resisting the effects of said discharge to reduce the depreciation ofsaid lamp.

3. A gaseous electric discharge lamp device comprising a container,electrodes sealed therein, a gaseous atmosphere therein rich in ultraviolet rays when excited by a discharge between said electrodes and aprotective coating on the inner surface of said container, saidcontainer consisting of ultra violet transmitting glass havingincorporated therein a material capable of light emission underexcitation by radiation from the gaseous electric discharge between saidelectrodes, said container glass being deleteriously affected by saiddischarge, said coating covering said light emitting container part andconsisting of boric acid to reduce the depreciation of said lamp.

4. A gaseous electric discharge lamp device comprising a container,electrodes sealed therein, a gaseous atmosphere therein rich in ultraviolet rays when excited by a discharge between said electrodes and aprotective coating on the inner surface of said container, saidcontainer consisting of ultra violet transmitting glass havingincorporated therein a material capable of light emission underexcitation by radiation from the gaseous electric discharge between saidelectrodes, said container glass being deleteriously affected by saiddischarge, said coating covering said light emitting container part andconsisting of phosphoric acid to reduce the depreciation of said lamp.

5. An article of manufacture consisting of a glass body having aluminescent material incorporated therein and a protective coating onsaid body, said glass body being deleteriously affected by a gaseouselectric discharge, said coating being resistant to said discharge.

6. A gaseous electric discharge lamp device comprising a container,electrodes sealed therein, a gaseous atmosphere therein comprisingmercury vapor rich in ultra violet rays when excited by a dischargebetween said electrodes and a protective coating on the inner surface ofsaid container, said container consisting of ultra violet transmittingglass having incorporated. therein a material capable of light emissionunder excitation by radiation from the gaseous electric dischargebetween said electrodes, said container ILLEM UY'I'ERHOEVEN.

